My MC33172 circuit is a mic preamp (like the TL071 mic preamp) plus a precision half-wave rectifier circuit but not needing a negative supply voltage. That is all you need.

Or instead you can use a TL071 mic preamp plus an LF351 precision half-wave rectifier that needs a negative supply voltage.

Both circuits will perform the same. Select one.

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Uncle $crooge

 

I choose the tl071 and the precision half wave rectifier..
I figured out how to give it a negative nine volt supply from an external dual power supply. I just have a concern of how to do that negative supply once im only working with bread boards or a pcb?
any suggestions?

 

Why don't you like my MC33172 circuit? It does not need a negative supply and it works perfectly in my project. It has more than 50dB range.

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Uncle $crooge

 

i dont have the parts in yet but i will. In the meantime,

for a negative voltage here is what i found. I tested it im getting negative 1 volt not negative 5 which is what im looking for. I found this schematic online through google.

My question is, what value of diode is supposed to be used based on the schematic any suggestions?

I would greatly apreciate it..

Attached Thumbnails

 

 

The 555 oscillator/rectifier circuit has two rectifier diodes and a 5.1V zener diode that limits its output voltage to -5.1V.
Maybe you connected the zener diode with backwards polarity.

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Uncle $crooge

 

i doubled checked polarities, Im thinking its the value of D1 AND D2,
which value should I use?

 

Use a 1N4001 rectifier diode for D1 and D2.

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Uncle $crooge

 

I tried the 1n4001 diodes again and im still getting -1 volts or so. what would you suggest to do to get a negative voltage?

 

Do you have the 5.1V zener diode connected with its cathode to ground?
What is the load on the -5.1V supply?

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Uncle $crooge

 

across the zener -5.1 diode i have -0.16v with the cathode to ground.

 

I dont have anything connected to the load.. just yet. If i get it to work i plan to connect it a circuit which has an tl 071 microphone op amp with an lf 351 precision half wave rectifier. Is there another rectifier circuit I can build that doesnt use negative voltage? or what can I do any suggestions?

 

Before you had -1V and now you have only -0.16V. I don't know why the output voltage is dropping.
Try another 555 IC and new 9V battery.

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Uncle $crooge

 

I replaced the 555 timer and now im getting negative one volts, the power is coming from a dc power supply not a nine volt battery but I dont suspect this would be the cause..

 

My MC33172 circuit is a mic preamp (like the TL071 mic preamp) plus a precision half-wave rectifier circuit but not needing a negative supply voltage. That is all you need.

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Uncle $crooge

 

Hi im not getting any audio like wave forms at output or pin1 and or output or pin 7. How can I check to see if I didnt blow my chip or what would you recommend to debug this?